Knowledge base

Calculation guides for installation engineers and designers — heating, ventilation, water & sewage, gas and electrical. Each article explains the formulas and standards step by step, and you can run the final result straight away in the linked calculator.

All (46)

Heating (12)

Pipes (7)

Units (6)

Electrical (4)

Ventilation (4)

Architecture (3)

Gas (3)

Sewerage (2)

Water Supply (2)

Installations (2)

Regulations (1)

Selecting overcurrent protection — MCBs, gG fuses and RCDs step by step

13 czerwca 2026 | Electrical

Selecting the cable cross-section is only half the job — the cable still has to be protected. A poorly chosen circuit breaker or fuse means a circuit…

U-Value Heat Transfer Coefficient - Building Envelope Insulation Guide

11 czerwca 2026 | Architecture

Heating costs account for 60-70% of total residential building operating expenses. The key parameter determining the quality of building envelope…

Low-pressure LPG installation — pipe sizing (propane and propane-butane mix)

29 maja 2026 | Gas

An LPG (liquefied petroleum gas) installation supplied from a domestic tank or a cylinder bank is, for many homes beyond the reach of the natural gas…

Pipe Water Capacity and System Water Volume — Formula, Table, Calculator

11 maja 2026 | Pipes

A fitter filling up the system wonders "how much glycol to pour in". A designer sizing the expansion vessel asks "what is the system water volume". A…

Hydraulic Balancing of Central Heating Systems — Flows, Settings and Valve Selection

6 maja 2026 | Heating

Hydraulic balancing of a central heating system means setting the flows so that each radiator, underfloor heating loop or other heat emitter receives…

Mollier diagram (i-x) - how to read it and use it in HVAC design practice

24 kwietnia 2026 | Ventilation

For the HVAC designer, the Mollier diagram is still the fastest way to see, at a single glance, what happens to the air inside an air handling unit…

Designing building sanitary drainage per PN-EN 12056-2

22 kwietnia 2026 | Sewerage

Incorrect sizing of a sanitary drainage system leads to blockages, backflow, water hammer and noise transmitted to habitable rooms — and, in extreme…

DHW cylinder sizing with DIN 4708 — N, N_L and an example for 60 flats

17 kwietnia 2026 | Water Supply

The most honest preliminary method for sizing a domestic hot water cylinder in a residential building, hotel or dormitory is not a fixed number of…

Building Heat Loss Calculations per EN 12831 — step-by-step guide

14 kwietnia 2026 | Heating

A heat loss balance is the foundation of every heating system design. The correct result determines boiler and heat pump sizing, radiator dimensions,…

How to calculate airflow in ventilation? Standards, air change rate and calculator

12 kwietnia 2026 | Ventilation

Designing a ventilation system always starts with the same question - how much air must be supplied to a room and how much must be removed from it…

Recuperation vs. natural ventilation - what to choose when building a house?

11 kwietnia 2026 | Ventilation

Ventilation is one of the key elements of every building - it affects comfort, residents' health and operating costs. In single-family houses, two…

Expansion Vessel Sizing for Heating Systems — Formulas, PN-B-02414, Calculator

9 kwietnia 2026 | Heating

An expansion vessel (also called a diaphragm expansion tank) is a component without which no closed heating system can operate safely. Its role is to…

Structural Design of Buried Pipes per ATV-A 127 — Designer's Guide

8 kwietnia 2026 | Pipes

Designing buried pipes — sewer, water and industrial — requires a structural check, independent of hydraulic calculations. A pipe placed in a trench…

Heating media — water, glycol and dilution tables for installations

7 kwietnia 2026 | Heating

What flows in our pipes, radiators — generally in heating systems? Most often it is, of course, plain water. However, there are other fluids found in…

Gas pipe sizing - calculations, standards, and practical examples

7 kwietnia 2026 | Gas

Correct gas pipe sizing is the foundation of a safe and efficient installation. Undersized pipes cause excessive pressure drop and improper operation…

Underfloor vs Radiator Heating - Comparison, Costs and System Selection

7 kwietnia 2026 | Heating

Choosing a heating system is one of the most important decisions during the construction or renovation of a home. Underfloor heating and radiator…

Steel pipes in sanitary installations - types, standards, and applications

7 kwietnia 2026 | Pipes

Steel pipes have been the foundation of sanitary, heating, and gas installations for over a hundred years. Despite the growing share of plastics…

Compressed air installation — design, calculations, and pipe sizing

7 kwietnia 2026 | Installations

Compressed air is one of the most commonly used energy carriers in industry — it is used to power pneumatic tools, control automation systems, spray…

Water Supply Pipe Sizing — calculations, standards and practical example

7 kwietnia 2026 | Water Supply

Correct pipe sizing is one of the key stages in designing an internal water supply installation. A diameter that is too small causes insufficient…

Pipe diameter table for plumbing installations — steel, copper, PP, PEX, AluPEX

4 kwietnia 2026 | Pipes

Selecting the correct pipe diameter is the foundation of every plumbing installation project. In practice, the designer needs to know not only the…

Electrical installation power balance — a practical guide for electricians

3 kwietnia 2026 | Electrical

The power balance is the foundation of every electrical installation design. Without a correct balance you cannot determine the connection capacity…

Safety valve selection in heating systems – standards, calculations, practice

1 kwietnia 2026 | Heating

A safety valve is a component that a designer hopes never to think about in terms of its activation — but must always think about in terms of its…

How to calculate underfloor heating step by step — a guide with calculator

29 marca 2026 | Heating

Underfloor heating is one of the most popular heating systems in new construction. However, correctly calculating the installation requires…

Voltage drop in electrical installations — how to calculate it and when it becomes a problem?

26 marca 2026 | Electrical

Every electrical cable resists the flow of current — the longer the cable and the higher the current, the more voltage is "lost" along the way. In…

Thermal Conductivity λ of Building Materials — Reference Tables

23 marca 2026 | Architecture

When calculating the U-value (thermal transmittance), the key parameter for each material is its thermal conductivity λ (lambda). The lower the λ…

Electrical Cable Cross-Section Selection — Step-by-Step Guide According to N-SEP-E-002

12 marca 2026 | Electrical

Proper selection of an electrical cable cross-section is the foundation of a safe and efficient installation. A cable that is too thin risks…

What Insulation Thickness for Walls, Roof and Floor? Guide with Tables

11 marca 2026 | Heating

How thick does wall insulation need to be? How many centimetres of mineral wool on the roof? What thickness of XPS under the floor? These are…

Ventilation Duct Sizing - Installation Designer's Guide

8 marca 2026 | Ventilation

Proper ventilation duct sizing is one of the key stages in designing a mechanical ventilation system. A duct that is too small means excessive noise…

How to Choose a Radiator? Step-by-Step Guide to Panel Radiator Selection

6 marca 2026 | Heating

Radiator selection is one of the key stages in designing a central heating system. A poorly chosen radiator means either an underheated room or…

New Technical Conditions 2026 in Poland - what changes from September 20?

20 lutego 2026 | Regulations

On September 20, 2026, a new regulation of the Minister of Development and Technology on the technical conditions to be met by buildings and their…

Pressure Drop Calculations in Medium and High Pressure Gas Pipelines

1 lutego 2026 | Gas

Calculating pressure drop in medium and elevated pressure gas pipelines (0.1-16 bar) requires the application of appropriate formulas that account…

Dew Point and Condensation in Building Partitions - Guide

18 stycznia 2026 | Heating

Moisture in building partitions is one of the most serious problems in modern construction. It can lead to mold growth, degradation of insulation…

Sound Insulation of Building Partitions Rw - Guide to PN-B-02151-3 Standard

17 stycznia 2026 | Architecture

Noise in residential buildings is one of the most common problems reported by residents. According to research by the Central Statistical Office…

Application for determining conditions for connection to water supply, sewage and gas networks

27 lipca 2025 | Installations

The procedure for obtaining connection conditions to water supply, sewage and gas networks is a key stage of any construction investment in Poland…

Hydraulic Calculations and Pipe Sizing in Gravity Sewerage Systems

16 lutego 2025 | Sewerage

Guide to flow calculations and pipe diameter selection in gravity sewerage systems according to Polish standards Designing gravity sewerage systems…

Units of Mass

21 października 2024 | Units

Units of mass (weight) play a crucial role in everyday life and science, allowing for precise measurement of the weight of various objects. Their…

Thermal Expansion in Installations and Beyond - Compensation Methods

5 września 2024 | Pipes

Thermal expansion of pipes is crucial for trouble-free operation of sanitary installations, as temperature changes affect their length. In this…

Unit Conversion - Real Life Stories

17 czerwca 2024 | Units

Units of measurement are the foundation of our civilization. They form a common language that allows us to compare distances, masses, energies, and…

Control Valve Authority - Kvs Coefficient

6 marca 2024 | Heating

The flow coefficient Kv (or kvs) is one of the key parameters that allows determining the optimal valve for a given hydraulic system. Valve kvs…

Speed Units

31 października 2023 | Units

Speed is a key parameter of motion, used in various fields, and speed units are an integral part of everyday life. Introduction Speed is one of the…

Length Units

14 września 2023 | Units

Length units are an integral part of our lives, allowing us to determine distances and sizes. Their history dates back thousands of years, reflecting…

Volume Units

2 kwietnia 2023 | Units

Volume units are numerical values used to describe the amount of space occupied by solids, liquids, and gases. In everyday life and science, we use…

Pressure Units

22 marca 2023 | Units

Pressure is a scalar physical quantity that defines the value of force acting perpendicular to a surface divided by the size of that surface…

PVC Pipes - Polyvinyl Chloride

30 listopada 2022 | Pipes

PVC Pipes - Pipes made of this material are most commonly associated with sewage systems. And that's really the case. This is the material most…

Polypropylene Pipes - PP

28 listopada 2022 | Pipes

Polypropylene pipes - one of the most commonly chosen pipes for sanitary installations, mainly water supply systems. Relatively cheap, easy to…

Calculating pressure drops and pipe sizing in heating systems

25 października 2022 | Heating

This article is dedicated to installers and other industry professionals who don't have experience with heating system calculations but would like to…